Anyone remember a BMX bike from the seventies that had a spring integrated into the fram, and the whole frame flexed? A buddy had one back in 78-9 time frame, but I have no idea who made the thing (or really, how to describe it).
I remember these, but I think that was '80s.
No, that wasn't it.
Seems like the spring went from the seat base to where the downtube met the headtube, but I could be wrong.
The spring looked like a chromed coilover.